Roll composition

ABSTRACT

An apparatus for use in combination with a traveling web, comprising a pair of rolls defining a nip between which said web passes, at least one of said rolls having an outer shell consisting of a nonwoven mat wrapping said roll and bonded with a thermosetting resin. Preferred nonwoven mats for the present invention are acrylic mats, while thermosetting resins most preferred are epoxy resins.

United States Patent s4 ROLL COMPOSITION 2 Claims, 2 Drawing Figs.

[52] (1.8. CI 162/358, 29/120, 29/132,100/176, 226/181 51 Int. Cl D211 3/00 [50] Field of Search 162/358; 29/120, 132; 226/190, 181; 100/155, 160, 162, 176

[56] References Cited UNITED STATES PATENTS 3,242,554 3/l966 Raymond 29/120 3,291,039 12/1966 Christie 100/162 3,460,222 8/1969 Mitchell 29/120 Primary Examiner-Richard A. Schacher Attorneys- Dirk J. Veneman, John S. Munday and Gerald A.

Mathews ABSTRACT: An apparatus for use in combination with a traveling web, comprising a pair of rolls defining a nip between which said web passes, at least one of said rolls having an outer shell consisting of a nonwoven mat wrapping said roll and bonded with a thermosetting resin. Preferred nonwoven mats for the present invention are acrylic mats, while thermosettin g resins most preferred are epoxy resins.

PATENTEB NUVZ IQYI 3617.445

24 FIG 2 DONALD A BRA FF'IORD INVENTOR.

HIS ATTORNEY ROLL COMPOSITION This application is a continuation-in-part of my copending application Ser. No. 784,606, filed Dec. 18, 1968.

The present invention relates to an apparatus comprising a pair of rolls defining a nip between which a web passes. At least one and preferably both of the rolls defining the nip have an outer shell consisting of a nonwoven mat wrapping the roll and bonded with a thermosetting resin. Such rolls are relatively easy and inexpensive to manufacture, and are resistant to corrosion and chemical attack. These nip-defining rolls are capable of operating at high nip pressures and at extremely high speeds.

The use of nip-defining pairs of rolls, where the rolls are defined by the present invention, includes the use of such a pair of rolls as a wet press nip in a paper machine. This wet press serves to eliminate a quantity of the water contained in the web while the web is on a felt run and prior to the time where the web is capable of supporting its own weight.

In addition, the present invention includes the use of at least one additional roll in nip-defining relationship with the pair of rolls of the present invention to form a calender stack. It has been found that passing paper through a nip defined by a pair of rolls which contain an outer shell consisting of a nonwoven mat wrapping this roll and bonded with acrylic resin is particularly effective imparting the desired finish to the paper.

The rolls of the present invention be manufactured from any fiber substance that my be formed into a nonwoven mat. It is preferred, however, that the mat itself has a tensile strength of at least 5 pounds per inch. Typical examples of materials which may be formed into suitable fibrous mats are nylon fibers, paper or paperboard of sufficient strength, acrylic fibers, polyester fibers, cellulose acetate and other acetate fibers, asbestos fibers, cotton and sisal fibers, polyamide fibers, rayon fibers, polyolefin fibers, and the like. Particularly suitable rolls have been prepared from acrylic nonwoven mats.

The thermosetting resins employed to bond the nonwoven mat are broadly defined as condensation polymers or copolymers formed through the reaction of the functional groups of the organic compound, with the possible elimination of water or similar byproducts. A wide variety of thermosetting resins may be employed. An example of these are phenolic resins which are the reaction product of phenols with aldehydes, such as phenol and formaldehyde.

Urea and melamine resins are also suitable and are formed from the reaction between the hydrogen of the amine groups of urea or melamine and the hydroxyl of the hydrated formaldehyde.

Two other closely related classes of thermosetting resins which may be employed are alkyds and polyesters, otherwise known as modified and unmodified polyester resins. Polyester resins are prepared by reacting a polybasic acid such as adipic acid, sebacic acid, etc. with a polyfunctional component such as glycol, glycerol, and the like. Modified or alkyd resins are formed by the reaction of a fatty glyceride or fatty acid such as linoleic acid with the unmodified resin.

The most preferred class of thermosetting resins are the epoxy resins. Epoxy resins are formed from a basic epoxide which contains epoxy groups which are then cured with either diamines or diabasic anhydrides. Epoxides are prepared in a number ofways, such by the reaction of phenol and acetone to produce Bisphenol-A, which in turn is reacted with epichlorohydrin to yield the epoxy intermediate. Diamine or diabasic anhydride then reacts with the intermediate to produce the final resin.

Another preferred class of thermosetting resins are the acrylic resins. Acrylic resins are acrylate or methacrylate ester polymers, although they may include acrylonitrile and chloroacrylate polymers. These polymers are polymerized alone or with other comonomers to give the acrylate resin.

As has been stated above, the nonwoven mat is wrapped around the roll core after being saturated with the resin in a conventional manner. Polymerization of the resin to bond a nonwoven mat results in the formation of them". Simple machining of the surface and conventional grooving may then be done to yield a grooved roll. As described in mycopending application having Ser. No. 784,606, filed Dec. 18, l968, the disclosure of which is incorporated herein by reference, the rolls of the present invention are capable of operating at high speeds and high nip pressures for significant periods of time.

For a more complete understanding of the operation of the rolls, and for a better understanding of the operation of the rolls, and for a better understanding of the necessity for resistance to corrosion at high nip pressures and speeds, reference is hereby made to the drawings in which:

H6. 1 represents a schematic view of one embodiment of the invention; and

FIG. 2 represents a schematic partially sectioned diagram of a second embodiment of the present invention.

As shown in FIG. 1, there is a web W which passes through a nip 14. The nip 14 is defined by a pair of rolls l0 and 12 which have outer coverings 11 and 13 consisting of nonwoven mats wrapping the roll and bonded with a thermosetting resin. As has been stated above, the preferred mat is an acrylic nonwoven mat, while the preferred resin is an epoxy resin. It has been observed that when the pair of rolls are operated as a wet press roll in a Fourdrinier paper machine, or other paper machines, the web passing through the nip is readily released, which is believed to be caused by the ability of the nonwoven shell 11 or 13 to carry water on its surface, thereby preventing the web from sticking to the roll.

As shown in H6. 2, the web W takes a serpentine path through a plurality of rolls 16, 18, 22 and 24. Roll 16 forms a nip 20 with roll 18, with nip 20 being defined by the outer shells l7 and 19 of the rolls l6 and 18. As is contemplated by the present invention, the outer shells l7 and 19 are formed from a nonwoven mat wrapping the roll and bonded with a thermosetting resin. Rolls 22 and 24 are also in nip-defining relationship with the pair of rolls. Use of such a combination to form a calender stack for use in the paper industry has been found to be substantially less expensive due to the readily machinable surfaces ofthe rolls of the present invention.

Having thus described the invention, what is claimed is:

1. In an apparatus for use in combination with a traveling web, including a pair ofrolls defining a nip between which said web passes, the improvement comprising a composite outer shell for both of said rolls, said shell comprising a composite derived from a nonwoven mat made from fibers selected from the group consisting of acrylic fibers, polyester fibers and mixtures thereof and bonded with a thermosetting resin of the epoxy type.

2. The apparatus of claim 1 wherein said pair of rolls forms a wet press nip in a papermachine. 

2. The apparatus of claim 1 wherein said pair of rolls foRms a wet press nip in a papermachine. 